Satellite Communications

This page shows my experiments in LEO/GEO satellite communication systems where I test the theory with practical measurements. This has given me experience in antenna design and build, rotators and control, Doppler shift and demodulating & decoding of signals.

Sat: Antenna Mk1
Sat: Antenna Mk2
Sat: Screen Setup
Sat: Example QSOs
Sat: Radio - ic9700
Sat: Software - WSJT-x
Sat: Software - SatPC32
Sat: Downloading Telemetry

Sat: Antenna Mk1

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Initially, my rotor was used for LEO and GEO satellites, with the following setup. In our garden though, elevations above about 30 degrees was required due to the trees and houses. So I simplified the satellite antenna and now use this rotor position for EME.

Sat: Antenna Mk2

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Here is my current satellite antenna: using the m2 leo pack with antennas pointing to zenith, it is possible to work leo satellites as low as 30-40 degrees elevation, since the yagi beamwidth is around -3dB at +/-45 deg and -6dB at +/-60 deg. Note that I reduced the 8+8 element 70cm antenna to 4+4 to achieve similar beamwidth to the 2m antenna, whilst only losing 3dB in antenna gain.

Sat: Screen Setup

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Fig: FT4 satellite setup on screen

Sat: Example QSOs

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Here are a few QSO made using FT4 over satellite

Callsign	Country	Satellite
ON8NT	Belgium	RS-44
F6HRO	France	RS-44
PD0HCV	Netherlands	RS-44
LA2XNA	Norway	RS-44
EA3GCV	Spain	RS-44

Sat: Radio - ic9700

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This is how I configure the Icom ic-9700 to work with WSJTx for FT4 over satellite.

Sat: Software - WSJT-x

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Sat: Software - SatPC32

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After testing a variety of satellite prediction software, I selected SatPC32 for my own station as it offers flexibility of setup and all the features I need.

Sat: Downloading Telemetry

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Using gr-satellites, I built a GNU radio receiver to demodulate and decode telemetry data from LEO satellites.

It is usually possible to download data about the health of the satellite such as battery voltage and temperatures.